Process of making a contoured thermal device

ABSTRACT

Heating and cooling patch in which liquid conducting passageways are formed between superposed sheets of flexible material. In one embodiment, tapered dart-shaped areas are provided at the edges of the sheets for forming the patch to a desired contour. In another embodiment, the patch is heat formed to the desired contour.

United States Patent [191 Elkins Aug. 20, 1974 I PROCESS OF MAKING A CONTOURED THERMAL DEVICE [75 Inventor:

[73] Assignee:

22 Filed: Feb. 28, 1973 211 Appl. No.: 336,615

52 U.S.Cl 156/289, 53/29, 62/530, 128/403, 150/2.1, 165/46, 156/290 51 Int. Cl ..B22b 31/00 [58] Field of Search 53/29; 128/399, 402, 403; 62/530; 150/2.1, 2.2; 156/289, 290; 165/46 William Elkins, San Jose, Calif.

Acurex Corporation, Mountain View, Calif.

{56] References Cited UNITED STATES PATENTS 3,092,112 6/1963 Zelony ISO/2.2 X 3,343,463 9/1967 Nielsen et a1. 156/289 X 3,463,161 8/1969 Andrassy 128/402 3,523,050 8/1970 Campbell 156/289 3,753,823 8/1973 Kuss [56/289 X FOREIGN PATENTS OR APPLICATIONS 697,820 10/1940 Germany 128/403 Primary ExaminerChar1es W. Lanham Assistant Examiner-D. C. Reiley, I11

Attorney, Agent, or FirmFlehr, Hohbach, Test, Albritton & Herbert [57] ABSTRACT Heating and cooling patch in which liquid conducting passageways are formed between superposed sheets of flexible material. In one embodiment, tapered dartshaped areas are provided at the edges of the sheets for forming the patch to a desired contour. In another embodiment, the patch is heat formed to the desired contour.

4 Claims, 5 Drawing Figures PAlzmmmzmw 3.830.676

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BACKGROUND OF THE INVENTION This invention pertains generally to devices for stabilizing and maintaining predetermined temperatures and more particularly to a device for heating or cooling by liquid circulation.

Bodies such as the human body and devices such as electronic or optical devices require thermal stabilization in a variety of circumstances. For example, when the human body is subjected to an unusual temperature environment, it may be necessary or desirable to heat or cool all or part of the body. Likewise, electronic instrumentsand optical devices may require heating or cooling in different environments.

Conductive heat transfer with gassesis ineffective for the purpose noted because of the low heat capacity of gas and the inefficiency of gas blowers. A somewhat more successful approach has been the circulation of a heating or cooling fluid through a thin, flexible panel in contact with the body or object to be heated or cooled. Such devices are generally flat, and even though they are flexible, they are difficult to use on contouredsurfaces. Non-uniform contact with the skin or contact in relatively small areas can make it necessary to use hotter or colder liquids than would otherwise be necessary. With cold liquids, this can result in 'vasoconstrictive reaction of the capillaries near the areas of contact.

SUMMARY AND OBJECTS OF THE INVENTION According to the invention, a heating and cooling patch is made by superposing two flat sheets of flexible material and sealing the sheets together in certain areas to form tapered plenum chambers and liquid flow passages. In one embodiment, the patch is contoured by cutting tapered dart-shaped areas in the edges of the sheets and drawing the material together at the dartshaped areas. In another embodiment, the patch is heated and deformed plastically to provide the desired contour.

It is in general an object of the invention to provide a new and improved thermal device for heating and cooling the human body, and other objects.

Another object of the invention is to provide a thermal device of the above character which is contoured to a desired shape.

Additional objects and features of the invention will be apparent from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of one embodiment of a thermal device incorporating the invention, the device being illustrated in a fiat condition prior to being contoured.

FIG. 2 is an enlarged sectional view taken along line 22 in FIG. 1. v

FIG. 3 is an isometric view of the thermal device shown in FIG. 1 after it is contoured.

FIG. 4 is a top plan view of another embodiment of a thermal device incorporating the invention prior to contouring.

FIG. 5 is an isometric view illustrating the manner in which the device shown in FIG. 4 is contoured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated in FIGS. 1-3, the thermal device includes superposed sheets 10 and 11 which are sealed together along outside edges 12 and 13 and along a plurality of spaced lines 14 intermediate the edges to form plenum chambers 16 and liquid flow passages 17. The

plenum chambers are located proximate to edges 12 and 13, and they are tapered, each having a large end 16a and a small end 16b. An inlet 18 and an outlet 19 are formed in sheet 13 at the large ends of the plenum chambers and provided with suitable flow lines 21.

Flow passages 17 extend between the plenum chambers and are generally parallel to each other. These passages are preferably spaced close together to maximize the conductive contact area of the device.

Sheets'lO and 11 are preferably made of a flexible, waterproof material such as rubber, synthetic rubber or a fabric coated with an elastomeric material. The

sheets are sealed together in the desired areas by a suitable process such as vulcanizing or heat sealing. In the vulcanizing process, a parting agent such as Teflon is applied to the surface of one of the sheets in the areas which are not to be'bonded. The parting agent is conveniently applied by spraying it through a stencil. The second sheet is placed on the coated sheet, and the sheets are heated and pressure is applied to the outer surfaces of the sheets, fusing the material together in the uncoated areas. In the heat sealing process, heat and pressure are applied only to the areas to be fused, and no parting agent is required.

The patch is contoured by cutting inwardly extending tapered dart-shaped areas 23 at spaced apart locations along the edges of the sheets. The material at the edges 23a and 23b of the dart-shaped areas is drawn together and sealed to give the patch the desired contour. The flow passages and plenum chambers can either extend across the dart-shaped areas or terminate at the dartshaped areas, as desired. In the patch illustrated, they extend across all of the dart-shaped areas except dartshaped area 24. At the edges of dart-shaped area 24, sheets 10 and 11 are sealed together to form a continuation of scaled edges 12 and 13.

The patch illustrated in FIGS. l-3 is designed for use in the crown of a helmet. It is combined with other patches of similar construction to form a complete thermal lining for the helmet. Tape is attached to the patches at their edges, and the patches are laced together by elastic cords passing through eyelets in the tape. Flow lines are connected between the inlets and outlets of different patches and to a source of heating or cooling liquid.

In the embodiment illustrated in FIGS. 4 and 5, a heating and cooling patch 30 is provided with a desired contour by heat forming, rather than by the use of dartshaped areas. This patch is made by superposing two sheets of thermoplastic material such as a thermoplastic fiber coated with an elastomeric material. The thermoplastic material has the property of softening when heated and hardening again when cooled. Suitable fabrics include nylon and polyester fabrics such as Dacron. Suitable materials for the elastomeric coating include urethane, natural rubber or a synthetic rubber such as neoprene.

The sheets are bonded together by heat sealing along edges 31 and 32 and along lines 33 to form plenum chambers 36 and flow passages 37. An inlet 38 and an outlet 39 communicate with the plenum chambers.

After the sheets are bonded together, the patch is flushed with a suitable parting agent such as polyvinyl alcohol. The patch is then heated to the plastic temperature of the fiber and formed to the desired contour. When cooled, the patch retains its contour and its flexibility. The parting agent is removed by flushing the patch with water or another suitable solvent.

The patch can be heated and formed in a single operation by molding it over the heated form 41, as illustrated in FIG. 5. Alternatively, it can be formed by a vacuum molding process.

It is apparent from the foregoing that a new and improved thermal control patch which can be made to conform to any desired contour has been provided. While only the presently preferred embodiments have been described herein, as will be apparent to those familiar with the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims.

I claim:

1. In a process for making a contoured thermal device adapted to carry a circulating liquid for maintaining a body to which the device is applied at a predetermined temperature, the steps of superposing two flat sheets of a flexible material, sealing the sheets together along their edges and along lines intermediate. said edges to form plenum chambers along two oppositely disposed edges and a plurality of flow passages extending between said plenum chambers, providing a fluid inlet and a fluid outlet in communication with the plenum chambers, forming at least one tapered dartshaped area extending inwardly from an edge of the sheets, and thereafter drawing the edges of the sheets together along the edges of the dart-shaped area and sealing the edges of the sheets together along the edges of the dart-shaped area.

2. A process for making a contoured thermal device as in claim 1 wherein the plenum chambers are tapered and the fluid inlet and outlet are provided at the larger ends of said chambers.

3. A process for making a contoured thermal device as in claim 1 wherein the dart-shaped area cuts through one of the plenum chambers and the drawn together edges of the sheets are sealed together along the edges of the dart-shaped area in such manner that the plenum chamber extends across the drawn together area to provide uninterrupted flow across said area.

4. A process for making a contoured thermal device as in claim I wherein the dart shaped area cuts through one of the flow passages and the drawn together edges of the sheets are sealed together along the edges of the dart-shaped area in such manner that the flow passage extends across the drawn together area to provide uninterrupted flow across said area. 

1. In a process for making a contoured thermal device adapted to carry a circulating liquid for maintaining a body to which the device is applied at a predetermined temperature, the steps of superposing two flat sheets of a flexible material, sealing the sheets together along their edges and along lines intermediate said edges to form plenum chambers along two oppositely disposed edges and a plurality of flow passages extending between said plenum chambers, providing a fluid inlet and a fluid outlet in communication with the plenum chambers, forming at least one tapered dart-shaped area extending inwardly from an edge of the sheets, and thereafter drawing the edges of the sheets together along the edges of the dart-shaped area and sealing the edges of the sheets together along the edges of the dart-shaped area.
 2. A process for making a contoured thermal device as in claim 1 wherein the plenum chambers are tapered and the fluid inlet and outlet are provided at the larger ends of said chambers.
 3. A process for making a contoured thermal device as in claim 1 wherein the dart-shaped area cuts through one of the plenum chambers and the drawn together edges of the sheets are sealed together along the edges of the dart-shaped area in such manner that the plenum chamber extends across the drawn together area to provide uninterrupted flow across said area.
 4. A process for making a contoured thermal device as in claim 1 wherein the dart-shaped area cuts through one of the flow passages and the drawn together edges of the sheets are sealed together along the edges of the dart-shaped area in such manner that the flow passage extends across the drawn together area to provide uninterrupted flow across said area. 